FEA User Beware !
(Source : MECHANICA Tutorial, By Roger Toogood, Ph.D., P.Eng)
Users of this (or any other FEA) software should be cautioned that, as in other areas of computer applications, the GIGO (“Garbage In = Garbage Out”) principle applies. Users can easily be misled into blind acceptance of the answers produced by the programs. Do not confuse pretty graphs and pictures with correct modeling practice and accurate results.
A skilled practitioner of FEA must have a considerable amount of knowledge and experience. The current state of sophistication of CAD and FEA software may lead non- wary users to dangerous and/or disastrous conclusions. Users might take note of the fine print that accompanies all FEA software licenses, which usually contains some text along these lines: “The supplier of the software will take no responsibility for the results obtained . . .” and so on. Clearly, the onus is on the user to bear the burden of responsibility for any conclusions that might be reached from the FEA.
We might plot the situation something like Figure 1. In order to intelligently (and safely) use FEA, it is necessary to acquire some knowledge of the theory behind the method, some facility with the available software, and a great deal of modeling experience.
Some quotes from speakers at an FEA panel at an ASME Computers in Engineering conference in the early 1990’s should be kept in mind:
“Don’t confuse convenience with intelligence.”
In other words, as more powerful functions get built in to FEA packages (such as automatic or even adaptive mesh generation), do not assume that these will be suitable for every modeling situation, or that they will always produce trust worthy results. If an option has defaults, be aware of what they are and their significance to the model and the results obtained. Above all, remember that just because it is easy, it is not necessarily right!
“Don’t confuse speed with accuracy.”
Computers are getting faster and faster and it is tempting to infer that improved technology yields improved results. This also means that they can compute an inaccurate model faster than before – a wrong answer in half the time is hardly an improvement!
And finally, the most important:
“FEA makes a good engineer better and a poor engineer dangerous.”
As our engineering tools get more sophisticated, there is a tendency to rely on them more and more, sometimes to dangerous extremes. Relying solely on FEA for design verification might be dangerous. Don’t forget your intuition, and remember that a lot of very significant engineering design work hasoccurred over the years on the back of an envelope. Let FEA become a tool that extends your design capability, not define it.
Thank You…..Everyone is Number One
Everyone is Number One 
